Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “learning and memory”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,351 records · Page 75Linked to original sources
PubMedDate not supplied

Immune system learning and memory quantified by graphical analysis of B-lymphocyte phylogenetic trees.

The immune system learns from its encounters with pathogens and memorizes its experiences. One of the mechanisms it uses for this purpose is the intra-individual evolution of antigen receptors on B lymphocytes, achieved via hypermutation and selection of antigen receptor variable region genes during an immune response. We have developed a novel method for analyzing the graphical properties of phylogenetic trees of receptor genes which have been mutated and selected during an immune response. In the study presented here, we address the artifacts introduced by experimental methods of cell collection for DNA analysis, the meaning of each parameter measured on the tree graphs, and the differences between the dynamics of the humoral immune response in different lymphoid tissues.

Adaptation, Physiological↗
PubMed1992

Memory-based learning in preweanling and adult rats after infantile x-irradiation-induced hippocampal granule cell hypoplasia.

Infantile exposure to x-irradiation induced severe hippocampal granule cell hypoplasia in preweanling and young adult rats. Hippocampally damaged pups, tested at 16 days of age, showed deficits in a memory-based discrimination based on single alternations of reward and nonreward when training was conducted at a 60-s intertrial interval (ITI) but not when conducted at a 30-s ITI. This deficit was still present at the 60-s ITI in animals x-irradiated in infancy and tested at 60-65 days of age. These data provide further support for the role of the hippocampus in intermediate-term memory and demonstrate, in a developmental context, the importance of an intact hippocampus in learning that depends on nonspatial memory.

Aging↗
PubMed2001

Pharmacological enhancement of synaptic efficacy, spatial learning, and memory through carbonic anhydrase activation in rats.

CA1 pyramidal cells were recorded in rat hippocampal slices. In the presence of carbonic anhydrase activators, comicrostimulation of cholinergic inputs from stratum oriens and gamma-aminobutyric acid (GABA)ergic inputs from stratum pyramidale at low intensities switched the hyperpolarizing GABA-mediated inhibitory postsynaptic potentials to depolarizing responses. In the absence of the activators, however, the same stimuli were insufficient to trigger the synaptic switch. This synaptic switch changed the function of the GABAergic synapses from excitation filter to amplifier and was prevented by carbonic anhydrase inhibitors, indicating a dependence on HCO. Intralateral ventricular administration of these same carbonic anhydrase activators caused the rats to exhibit superior learning of the Morris water maze task, suggesting that the GABAergic synaptic switch is critical for gating the synaptic plasticity that underlies spatial memory formation. Increased carbonic anhydrase activity might, therefore, also enhance perception, processing, and storing of temporally associated relevant signals and represents an important therapeutic target in learning and memory pharmacology.

Acetazolamide↗
PubMed2003

Comparison of the effect of NT-0409 and antidementia drugs on learning and memory in rats with chronic cerebral cholinergic deficiency.

Systemic oral administration of NT-0409, a new synthetic agonist of AMPA subtype glutamate receptor, to rats with chronic partial AF64A-induced deprivation of cholinergic functions improved their learning in a Morris water maze. NT-0409 is close to memantine by the effect on learning and, in contrast to cholinomimetic arisept, ensures longer retention of the developed habit.

Alzheimer Disease↗
PubMed1997

Measures of spatial memory and routes of learning.

Spatial memory was investigated in two experiments by direct methods. Methods included scaling of distances, estimation of bearings, and positioning of objects. Participants learned small-scale configurations under different orders of presentation. In Exp. 1, routes included a shortest path, i.e., a traveling salesman solution, a random sequence, and a path that maximized distances. In Exp. 2, spatial and temporal distances varied independently. It was analyzed whether the different methods yielded the same information. For bearing estimates a new scaling procedure was developed. Computations resulted in two-dimensional Euclidean solutions in close correspondence with the stimulus configuration. In addition, solutions showed an effect of temporal conditions of learning.

Attention↗
PubMed1986

Memory in learning disabled children: digit span and the Rey Auditory Verbal Learning Test.

Scores on the Rey Auditory Verbal Learning Test (RAVLT) were compared to WISC-R digit span results in a sample of 153 learning disabled students. With statistical controls for age and IQ, regression analyses indicated no significant relationships between the RAVLT and longest forward span, longest backward span and total digit span raw score. Factor analysis of the RAVLT variables, forward span, backward span and total digit span raw score yielded three factors that were interpreted to represent a long term memory factor, a short-term memory factor with high coding demands and a short-term memory factor with low coding demands. Conclusions were made regarding the inadequacy of using only digit span when making diagnostic statements about the auditory memory functioning of learning disabled students.

Journal Article↗
PubMed1993

Effects of chronic cocaine abuse on memory and learning.

Sixteen chronic (M = 5 years) weekly cocaine users who were at least 10 days (M = 20 days) abstinent were compared to age, education, race, and gender matched controls on the California Verbal Learning Test, Wechsler Adult Intelligence Scale-Revised (WAIS-R) Vocabulary, and Block Design. Subjects with developmental disorder, neurological, psychiatric, or other substance abuse history were excluded. Cocaine subjects learned and recalled fewer words than controls, but did not differ on IQ. Results suggested significant residual impairment in verbal learning efficiency subsequent to chronic cocaine use that results from memory storage difficulties rather than attentional impairment or general intellectual reduction. A dose-response relationship is suggested.

Journal Article↗
PubMed2002

Knockout of ERK1 MAP kinase enhances synaptic plasticity in the striatum and facilitates striatal-mediated learning and memory.

Extracellular signal-regulated kinases (ERK1 and 2) are synaptic signaling components necessary for several forms of learning. In mice lacking ERK1, we observe a dramatic enhancement of striatum-dependent long-term memory, which correlates with a facilitation of long-term potentiation in the nucleus accumbens. At the cellular level, we find that ablation of ERK1 results in a stimulus-dependent increase of ERK2 signaling, likely due to its enhanced interaction with the upstream kinase MEK. Consistently, such activity change is responsible for the hypersensitivity of ERK1 mutant mice to the rewarding properties of morphine. Our results reveal an unexpected complexity of ERK-dependent signaling in the brain and a critical regulatory role for ERK1 in the long-term adaptive changes underlying striatum-dependent behavioral plasticity and drug addiction.

Amygdala↗
PubMed1987

[Effect of sidnocarb on learning and memory].

It has been established that in well-trained rats sydnocarb (mesocarb) does not exert a considerable effect on the generation of conditioned reflex of passive avoidance (CRPA). On the contrary, in poorly-trained animals sydnocarb significantly improves CRPA indexes at all three stages of its generation. Sydnocarb proved most effective, when injected before training (on day I). The absence of sydnocarb-induced pain threshold decrease in response to electrical pain stimulation suggests a direct drug effect on memory processes.

Animals↗
PubMed1989

Effects of the novel compound, Hoe 065, upon impaired learning and memory in rodents.

The effects of Hoe 065 (n-octyl 2-[N-[(S)-1-ethoxycarbonyl-3-phenylpropyl]-L-alanyl]-(1S,3S, 5S)-2-azabicyclo [3.3.0]octane-3-carboxylate maleate salt) were studied on the performance of mice and rats in different learning tasks. Hoe 065 prevented the disruption of memory induced by scopolamine administered before training. The results indicate that Hoe 065 improves cognitive function in different tasks.

Animals↗